STUDIES ON POLYNUCLEOTIDES .92. SYNTHESIS OF A DEOXYRIBODODECANUCLEOTIDE CONTAINING SPECIFIC AMINO ACID CODONS

High molecular weight deoxyribopolynucleotides with repeating nucleotide sequences have previously been shown to direct the synthesis of polypeptides in the bacterial cell-free protein synthesizing system. With the aim of synthesizing polypeptides containing specific amino acid sequences via nucleic acid templates, a deoxyribododecanucleotide has now been synthesized. The synthetic polynucleotide, d-A-T-G-C-A-C-T-C-T-T-A-G, contains at the appropriate 5ʹ end the trinucleotide sequence A-T-G, which stands for formylmethionine and initiates the synthesis of peptide chain, and at the 3ʹ end the sequence T-A-G, which should terminate and release the polypeptide chain. The codons selected for internal positions were C-A-C (histidine) and T-C-T (serine). The protected trinucleotide blocks d-MMTr-ABzpTpGiBV3 d-pCAnpABzpCAn-OAc, d-pTpCAnpT-OAc,3 and d-pTpABz-pGiBu-OAc3 were prepared by stepwise methods using the protected nucleoside and nucleotides. The blockwise condensations of the protected trinucleotides to form the dodecanucleotide were carried out using mesitylenesulfonyl chloride as the condensing agent, yields in the individual steps being 30-50%. © 1969, American Chemical Society. All rights reserved.